Furnace wall



1941- M. H. KUHNER 2,263,004

FURNACE WALL Filed Feb. 14, 1939 HHHHHHHHHHHHHE- E E CD /5- T 3:

D Fig. gwuem co o MAX H. K UHNER altar/wag Patented Nov. 18, 1941 UNITED STATES PATENT OFFICE 2,263,004 FURNACE WALL Max H. Kuhner, Worcester, Mass., assignor to Riley Stoker Corporation, Worcester, Mass., a

corporation of Massachusetts Application February 14, 1939, Serial No. 256,303

2 Claims. (Cl. 122-6) of closely spaced vertical water tubes II on thefurnace side of thewall to support the refractory surface is exposed there is a'possibility of lowering the furnace temperature excessively and causing difficulty in maintaining ignition of the fuel, particularly at low combustion rates. This has been recognized, and various schemes have been proposed for securing blocks to the tubes or otherwise protecting them to some extent from the radiant heat. however, have been complicated and expensive, subject to rapid deterioriation in service, and not readily adaptable to changes which may take place in the operating conditions.

It is accordingly one object of the invention to provide a water cooled wall of simple and inex pensive construction particularly suitable for furnaces in which pulverized fuel is burned in suspension. I i It is a further object of the invention to provide a water cooled furnace wall adapted to facilitate ignition of the fuel and capable of withstanding severe operating conditions throughout a long life of service.

It is a further object of the invention to provide a water cooled furnace wall which can be readily altered to vary the furnace temperature.

as may be desirable due to changes in the fuel used or other conditions of operation.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

. "Referring to the drawing illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. 1 is a vertical section through a water cooled furnace wall, the section being taken on the line l1 of Fig. 2;

Fig. 2 is an elevation of the wall as viewed from the inside of the furnace;

Fig. 3 is a section on the line 3-3 of Fig. 2; and

Fig. 4 is a perspective view of a refractory block.

The embodiment illustrated comprises an upright wall ill of refractory material and a row These prior constructions,

material and protect it from the heat of the furnace, these tubes serving also for the generation of steam. The lowerends of the tubes II are connected to a horizontal header [2, and their upper ends are connected to a horizontal header M. In order to avoid undue weakening of the headers, the ends of the tubes are staggered.

As shown particularly in Fig. 1, the successive tubes enter each header alternately in a vertical plane passing through the axis of the header and in an axial plane inclined inwardly toward the furnace at an angle of approximately 45 degrees from theverticalr Any suitable and well-known connections may be provided to deliver water to the lower header l2 and to remove water and steam from the upper header I4.

The construction as so far described presents toward the furnace a water-cooled metallic surface which will absorb radiant heat at a high rate, thereby reducing the temperature of the combustion chamber. In some cases, particularly when burning pulverized fuel under conditions of relatively low demand, the temperature may be reduced below the point at which ignitionof the fuel can be maintained, and the flame will be extinguished.

In order to avoid this difflculty I provide a row i of spaced upright columns l5 of refractory material, located in a vertical plane parallel with the tubes II and spaced inwardly therefrom toward the furnace. In order to support and cool these columns, I provide upright water tubes J6 which extend through the columns. These tubes l6 are bent at their ends to connect with the headers, and as shown in Fig. 1 they preferably enter each header in the horizontal axial plane.

Moreover, each tube I6 is located directly opposite one of the tubes II which connects with the headers in the vertical axial plane, this construction contributing to the maintenance of adequate strength in the headers. The weight of the columns l5 rests upon suitable lugs or shelves l8 which are welded or otherwise secured to the tubes l6.

While the columns l5 may be constructed in various ways, they are preferably formed of separate preformed blocks [9 of refractory material. As shown particularly in Fig. 4, each block I9 is shaped as a semi-circle, with a semicircular groove 20 therein to fit the outside of the tubes it. At each end of the block there is provided a pair of projecting lugs 22 separated by a recess 23. Each lug 22 extends through an 1 claim as new Patent is:

angle'of approximately 45 degrees, and each recess 23 extends through an angle of approximately 90 degrees. The blocks are mounted on the tubes IS in pairs, with each pair of blocks turned 90 degrees with respect to the-pair therebeneathr In this manner the lugs 22 enter the recesses 23 on the adjacent blocks, and all the blocks are firmly held in position'on the tubes.

In the operation of the furnace, the refractory columns l5.wil1 reach a high temperature by 1 reason of the heat which is radiated to them 1 from the combustion flame, and the columns in turn will radiate heat into the furnace and toward the incoming fuel. At the same time these columns will serve as shields to decrease the j transmission of radiant heat from the fumace to the bare water tubes ll. nace temperature will be raised, combustion conditions will be more stable, and ignition can be maintained even at lowfuel-burning rates. By, adding more blocks l9 or removing some of these a 1 blocks, the height of thecolumnslS can be varied 1 to provide the best average operating conditions in a particular installation. The water tubes l6 not only support the blocks l9 but they also serve 1 to protect these blocks from overheating, and in 1 addition they generate steam and thus increase l the'capacity of the installation. The entire con- ;struct-ion is relatively simple and inexpensive, and well adapted for a long life of service.

As a result the fur- Having thus described my invention, what I and desire-to secure, by Letters 1. A water cooled furnace wall comprising a row of relatively closely spaced upright water tubes, 9. second row of relatively widely spaced upright water tubes spaced inwardly from the first row, refractory material mounted on the tubes of the second row to form vertical columns which are spaced apart to allow the passage of radiant heat outwardly between them, 'a substantially horizontal header connected to the lower ends of both rows of tubes and arranged to supply water thereto for the generation of steam, and a substantially horizontal header water tubes spaced apart comparatively widely and connected at their ends to theheaders in substantially the horizontal axial planes of the headers, each tube in the inner'row being located f directly opposite one of the first-mentioned tubes,

and refractory materialmountecl on the tubes of the said inner row toform vertical columns which are spaced apart to allow the passage of- 1 radiant heat outwardly between them.

' MAX H. KUHNER. 

